Palos Heights police say they interrupted an attempted armed robbery at a 7-Eleven on West 135th Street early Friday morning, with three people taken into custody in Chicago and Hammond, Indiana.

Police reported being notified of an attempted armed robbery and vehicle theft near Southwest Highway and Harlem Avenue in Worth, as well as an armed robbery on the 11400 block of Harlem Avenue, both involving two men with handguns.

About 2 a.m. Friday, a Palos Heights officer on routine patrol driving through the 7-Eleven parking lot spotted a man behind the convenience store counter pointing a handgun at the clerk, police said in a news release.

When the man saw the squad car, he alerted another person in the store management office and both fled out the back door, police said.

Upon seeing a black Chrysler 200 turning west on 135th Street from a nearby residential street, the officer conducted a traffic stop.

The female driver initially stopped but then drove off after the officer commanded her to get out of the car., police said.

Chicago police later alerted the Palos Heights department that one suspect was in custody and the vehicle was heading toward Hammond, police said. Police there then stopped the vehicle and took the second offender and the female driver into custody.

Police said the 7-Eleven robbery was interrupted so the suspects did not leave with any money or merchandise. Police continue to investigate.

ostevens@chicagotribune.com